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JuliusBrussee/lean-build

Build feature work with high overbuilding risk. Use for new behavior, product slices, or integrations where repository reuse, strict scope, and an explicit stop condition matter.

What is lean-build?

lean-build is a Claude Code agent skill that build feature work with high overbuilding risk. Use for new behavior, product slices, or integrations where repository reuse, strict scope, and an explicit stop condition matter.

Works with~Claude Code~Codex CLI~Cursor
npx skills add https://github.com/JuliusBrussee/caveman/tree/main/skills/lean-build

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Documentation

Lean build

Native Core's architecture-first simplicity remains mandatory. Turn feature into complete narrow outcome fitting system.

  • Derive observable acceptance and explicit non-goals from request and repository.
  • Trace entry point through layers owning invariants.
  • Deliver coherent end-to-end path across responsible layers; never force work into one file, direct expression, or local patch.
  • Reuse fitting seam. Refactor when patching duplicates behavior, weakens ownership, or hides root cause.
  • Omit modes, providers, config, extensibility, and polish unless acceptance needs them.
  • Add surface, dependency, service, config, or migration only for lifecycle design or acceptance; state material tradeoff.
  • Keep work runnable; preserve Core safety.

Exercise path. Run focused proof. Stop when acceptance passes. Report only material omissions and trigger.

Individual skills in this repo

This repo contains 12 individual skills — each has its own dedicated page.

JuliusBrussee/caveman-discover

Find and label every LLM workflow in the repository so Caveman Cloud groups spend by workflow instead of one bucket. Use for "discover workflows" or breaking LLM spend down by workflow.

JuliusBrussee/caveman-evidence-review

Read-only review of Caveman Cloud evidence: cost, Cave Score, workflows, traces, latency, errors, routing, savings. Use when asked what Caveman found or where LLM spend goes.

JuliusBrussee/caveman-explore

Read-only repository explorer for cold-start orientation, broad cross-file localization, or when a direct search failed. Skip it when the exact file or symbol is already named. Returns path:line citations only; its reads stay out of main context.

JuliusBrussee/caveman-learn

Act on a Caveman learn report - review the ranked token sinks, apply cost-lowering fixes with per-edit consent, and report what those fixes returned. Use when asked to lower an agent's token cost, what caveman has saved, to trim a heavy CLAUDE.md, or to offload re-pasted context into cavemem.

JuliusBrussee/caveman-manage

Inspect Caveman Cloud's experiment lifecycle and block unsafe execution. Use when asked to start, approve, cancel, promote or roll back a Caveman experiment.

JuliusBrussee/caveman-optimize

Turn a Caveman optimization observation into an operator-chosen candidate with a paired baseline evaluation. Use when asked to inspect or evaluate a Caveman optimization report. Needs explicit approval.

JuliusBrussee/caveman-setup

Wire a repository through the Caveman Cloud gateway so every LLM request is measured, with no behavior change. Use for "set up caveman" or adding LLM spend observability.

JuliusBrussee/investigate-first

Diagnose ambiguous failures before editing. Use for unknown causes, intermittent behavior, performance regressions, or investigations needing evidence-ranked hypotheses.

JuliusBrussee/migration

Implement reversible compatibility-safe transitions. Use for schema, data, API, protocol, configuration, or dependency migrations requiring rollback and preservation proof.

JuliusBrussee/safe-refactor

Restructure code while preserving behavior. Use for extraction, consolidation, ownership moves, or cleanup where verification must bracket structural edits.

JuliusBrussee/surgical-patch

Fix bugs and small behavior changes at the narrowest responsible layer. Use when regression proof, preserved surrounding behavior, and task-relevant tests matter.

JuliusBrussee/verify-and-stop

Prove existing work meets acceptance conditions without expanding scope. Use for validation-only tasks, completion checks, focused gate runs, and last-mile proof.

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